The present invention measures first and second detection signals respectively obtained at two focuses during a focus search by means of an optical head 2. Then, a type of a disk-shaped optical record medium is determined by a microcomputer in a system controller 7, from a comparison between characteristics of the first and second measured detection signals. Moreover, the present invention can measure an amplitude and a frequency of the detection signal obtained at the focus during the focus search to thereby determine the type of the disk by using the measured result. After the parameters are set in accordance with the determined result, the focus servo control is turned on. The present invention comprises a selecting means for suitably switching and selecting between two types of tracking error signals, measures first and second detection signals respectively obtained at two focuses during a focus search, determine a type of a disk-shaped optical record medium by using the first and second measured detection signals and then controls the selecting means in accordance with the determined disk type. Moreover, the present invention measures an amplitude and a frequency of the detection signal obtained at one focus during the focus search, determines the disk type by using the measured result and then controls a timing at which a servo control is turned on in accordance with a conformity of a lens to the disk.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A disk type determining apparatus used in an optical disk reproducing apparatus which comprises: optical head which emits laser beams to a first or second type of optical disk such that the laser beams are collected through an optical system to first focus point and second focus point, the first focus point corresponding to a signal recording plane of the first type of optical disk having a first thickness, the second focus point corresponding to one or two signal recording plane(s) of the second type of optical disk having a second thickness which is different from the first thickness, and the optical head having a plurality of light sensor portions for detecting the reflected light of the laser beams; focus search means for moving said optical head or said optical system in a focus direction to thereby perform a focus search; measuring means for measuring levels of a first detection signal and a second detection signal, both of which are the output signals from said optical head respectively obtained in relation to the positions of the first and second focus points during the focus search by said focus search means; and determining means for determining one type among the first type of the optical disk and the second type of the optical disk having a single signal recording plane, or among the first type of the optical disk and the second type of the optical disk having two signal recording planes by using the levels of the first detection signal and the second detection signal, both of which are measured by said measuring means.
2. A disk type determining apparatus used in an optical disk reproducing apparatus which comprises: optical head which emits laser beams to a first or second type optical disk such that the laser beams are collected through an optical system to first focus point and second focus point, the first focus point corresponding to a signal recording plane of the first type of the optical disk having a first thickness, the second focus point corresponding to one or two signal recording plane(s) of the second type of the optical disk having a second thickness which is different from the first thickness, and the optical head having a plurality of light sensor portions for detecting the reflected light of the laser beams; first generating means for generating a first tracking error signal corresponding to the first type of the optical disk; second generating means for generating a second tracking error signal corresponding to the second type of the optical disk; selecting means for selecting any one of the first tracking error signal from said first generating means and the second tracking error signal from said second generating means; focus search means for moving said optical head or said optical system in a focus direction to thereby perform a focus search; measuring means for measuring levels of a first detection signal and a second detection signal, both of which are the output signals from said optical head respectively obtained in relation to the positions of the first and second focus points during the focus search by said focus search means; determining means for determining one type among the first type of the optical disk and the second type of the optical disk having a single signal recording plane, or among the first type of the optical disk and the second type of the optical disk having two signal recording planes by using the levels of the first detection signal and the second detection signal, both of which are measured by said measuring means; and control means for controlling said selected means so as to select the first tracking error signal from said first generating means when the first type of the optical disk is provided, or so to select the second tracking error signal from said second generating means when the second type of the optical disk is provided.
3. The disk type determining apparatus according to claim 2 , further comprises: second control means for setting circuit parameters to be set depending on a kind of said optical disk in accordance with said kind being determined.
4. A disk type determining apparatus used in an optical disk reproducing apparatus which comprises: optical head which emits laser beams to a first or second type optical disk such that the laser beams are collected through an optical system to a first focus point and a second focus point, the first focus point corresponding to a signal recording plane of the first type of the optical disk having a first thickness, the second focus point corresponding to one or two signal recording plane(s) of the second type of the optical disk having a second thickness which is different from the first thickness, and the optical head having a plurality of light sensor portions for detecting the reflected light of the laser beams; first generating means for generating a first tracking error signal corresponding to the first type of the optical disk; second generating means for generating a second tracking error signal corresponding to the second type of the optical disk; selecting means for selecting any one of the first tracking error signal from said first generating means and the second tracking error signal form said second generating means; focus search means for moving said optical head or said optical system in a focus direction to thereby perform a focus search; measuring means for measuring levels of a sum of all signals or a focus error signal obtained from said optical head during the focus search by said focus search means; determining means for determining one type among the first type of the optical disk and the second type of the optical disk having a single signal plane or among the first type of the optical disk and the second type of the optical disk having two signal planes by using the levels of the sum of all signals or the focus error signal, both of which are measured by said measuring means; and control means for controlling said selected means so as to select the first tracking error signal from said first generating means when the first type of the optical disk is provided, or so to select the second tracking error signal from said second generating means when the second type of the optical disk is provided.
5. The disk type determining apparatus according to claim 4 , further comprises: second control means for setting circuit parameters to be set depending on a kind of said optical disk in accordance with said kind being determined.
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April 2, 2001
August 19, 2003
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